Catalyst blends for producing low thermal desorption polyurethane foams

ABSTRACT

A catalyst composition for catalyzing a polyurethane forming reaction includes a gelling catalyst and a blowing catalyst selected such that the resulting polyurethane foam has a low level of volatile and/or malodorous material in it. The gelling catalysts are selected from tertiary aminoalkyl substituted primary or secondary amines; and the blowing catalysts are selected from bis(aminoalkyl) ethers comprising alkanol moieties, primary amine moieties, or ureido moieties derived from such primary amine moieties.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. Ser. No. 10/695,515 filed onOct. 27, 2003.

BACKGROUND OF THE INVENTION

The present invention relates to compositions and processes for makingpolyurethane foams. More particularly, it relates to compositions andprocesses incorporating tertiary amine catalysts capable of providingfoams having reduced levels of odor and volatile emissions.

Polyurethane foams are widely known and used in automotive, housing andother industries. Such foams are produced by reaction of apolyisocyanate with a polyol in the presence of a catalyst and a blowingagent, historically a chlorofluorocarbon (CFC) compound. Due toenvironmental concerns relating to CFC's, the use of water blown foamformulations, in which at least some of the blowing is performed withCO₂ generated by the reaction of water with the polyisocyanate, hasbecome increasingly important. Such systems typically employ tertiaryamine catalysts to accelerate both the blowing (reaction of water withisocyanate to generate CO₂) and gelling (reaction of polyol withisocyanate) reactions required to make a foam. However, known tertiaryamine catalyst compositions may give rise to objectionable releases ofvolatile and often malodorous materials into the air during foammanufacture and/or thereafter. The present invention addresses the issueof how to reduce such emissions, using certain catalyst compositions.

BRIEF SUMMARY OF THE INVENTION

In one aspect, the invention is a catalyst composition comprising:

1) a gelling catalyst represented by the general formula:

in which:

A represents CH or N,

R¹ represents hydrogen or the group

n represents an integer between 1 and 3, inclusive,

R² and R³ each represent hydrogen or a C1-C6 alkyl group, and

R⁶ represents H or 3-aminopropyl, provided that:

when A is N, R⁴ and R⁵ each represents a C1-C6 alkyl group or togetherrepresent a C2-C5 alkylene group which may contain a ring amine moiety—NR—, where R is hydrogen, a C1-C4 alkyl group, or the group

and

when A is CH, R⁴ and R⁵ together represent a C2-C5 alkylene groupcontaining a ring amine moiety —NR—, where R is a C1-C4 alkyl group orthe group

and

2) a blowing catalyst according to the general formula:

wherein:

R⁷, R⁸, and R⁹ each independently represents a C1-C4 alkyl group;

R¹⁰ represents H, a C1-C4 alkyl group, a C6-C20 aryl group, or a C6-C20aralkyl group;

m, p, and q each independently represents an integer between 1 and 4,inclusive; and Z represents —OH, —NH₂, —NH—CO—NH₂, or

In another aspect, the invention is a formulation for producing apolyurethane foam, the formulation comprising a polyol, apolyisocyanate, water, and a catalyst composition comprising:

1) a gelling catalyst represented by the general formula:

in which:

A represents CH or N,

R¹ represents hydrogen or the group

n represents an integer between 1 and 3, inclusive,

R² and R³ each represent hydrogen or a C1-C6 alkyl group, and

R⁶ represents H or 3-aminopropyl, provided that:

when A is N, R⁴ and R⁵ each represents a C1-C6 alkyl group or togetherrepresent a C2-C5 alkylene group which may contain a ring amine moiety—NR—, where R is hydrogen, a C1-C4 alkyl group, or the group

and

when A is CH, R⁴ and R⁵ together represent a C2-C5 alkylene groupcontaining a ring amine moiety —NR—, where R is a C1-C4 alkyl group orthe group

and

b 2) a blowing catalyst according to the general formula:

wherein:

R⁷, R⁸, and R⁹ each independently represents a C1-C4 alkyl group;

R¹⁰ represents H, a C1-C4 alkyl group, a C6-C20 aryl group, or a C6-C20aralkyl group;

m, p, and q each independently represents an integer between 1 and 4,inclusive; and Z represents —OH, —NH₂, —NH—CO—NH₂, or

In yet another aspect, the invention is a polyurethane foam comprising aproduct of a reaction between a polyol and a polyisocyanate, thereaction taking place in the presence of water and a catalystcomposition comprising:

1) a gelling catalyst represented by the general formula:

in which:

A represents CH or N,

R¹ represents hydrogen or the group

n represents an integer between 1 and 3, inclusive,

R² and R³ each represent hydrogen or a C1-C6 alkyl group, and

R⁶ represents H or 3-aminopropyl, provided that:

when A is N, R⁴ and R⁵ each represents a C1-C6 alkyl group or togetherrepresent a C2-C5 alkylene group which may contain a ring amine moiety—NR—, where R is hydrogen, a C1-C4 alkyl group, or the group

and

when A is CH, R⁴ and R⁵ together represent a C2-C5 alkylene groupcontaining a ring amine moiety —NR—, where R is a C1-C4 alkyl group orthe group

2) a blowing catalyst according to the general formula:

wherein:

R⁷, R⁸, and R⁹ each independently represents a C1-C4 alkyl group;

R¹⁰ represents H, a C1-C4 alkyl group, a C6-C20 aryl group, or a C6-C20aralkyl group;

m, p, and q each independently represents an integer between 1 and 4,inclusive; and Z represents —OH, —NH₂, —NH—CO—NH₂, or

In a further aspect, the invention is a method of making a polyurethanefoam, the method comprising mixing together a polyol, a polyisocyanate,water, and a catalyst composition comprising:

1) a gelling catalyst represented by the general formula:

in which:

A represents CH or N,

R¹ represents hydrogen or the group

n represents an integer between 1 and 3, inclusive,

R² and R³ each represent hydrogen or a C1-C6 alkyl group, and

R⁶ represents H or 3-aminopropyl, provided that:

when A is N, R⁴ and R⁵ each represents a C1-C6 alkyl group or togetherrepresent a C2-C5 alkylene group which may contain a ring amine moiety—NR—, where R is hydrogen, a C1-C4 alkyl group, or the group

and

when A is CH, R⁴ and R⁵ together represent a C2-C5 alkylene groupcontaining a ring amine moiety —NR—, where R is a C1-C4 alkyl group orthe group

2) a blowing catalyst according to the general formula:

wherein:

R⁷, R⁸, and R⁹ each independently represents a C1-C4 alkyl group;

R¹⁰ represents H, a C1-C4 alkyl group, a C6-C20 aryl group, or a C6-C20aralkyl group;

m, p, and q each independently represents an integer between 1 and 4,inclusive; and Z represents —OH, —NH₂, —NH—CO—NH₂, or

DETAILED DESCRIPTION OF THE INVENTION

Catalyst compositions according to the invention comprise a gellingcatalyst and a blowing catalyst, both of which comprise tertiary aminegroups. The gelling catalyst additionally comprises a primary orsecondary amine group. The blowing catalyst additionally comprises oneor more of a primary or secondary amine group, a hydroxyl group, and aurea group. Without wishing to be bound by any particular theory orexplanation, it is believed that the presence of such functional groupsprovides hydrogen bonding ability with the polyol(s) and orpolyisocyanate(s) used in making the polyurethane foams, as well as withchemical functionalities in the foams themselves, resulting in reducedvolatility and odor when compared with related tertiary amine catalystslacking these functional groups. It is further believed that thesefunctional groups may allow reaction of these catalysts into thepolyurethane foam, thereby preventing or at least reducing their releasefrom the foams.

The present invention provides catalyst compositions for makingpolyurethane foams, and methods for using these compositions. Thecatalyst compositions comprise mixtures of gelling catalysts selectedfrom tertiary aminoalkyl substituted primary or secondary amines; andblowing catalysts selected from bis(aminoalkyl) ethers comprisingalkanol moieties, primary amine moieties, or ureido moieties derivedfrom such primary amine moieties. The catalyst compositions producepolyurethane foams that have low amine odor and low catalyst-derivedemissions, as measured by thermal desorption testing techniques.

The present invention provides catalyst compositions suitable forcatalyzing the reaction between an isocyanate functionality and anactive hydrogen-containing compound, i.e. an alcohol, a polyol, an amineor water. In particular, the catalyst compositions catalyze the urethane(gelling) reaction of polyol hydroxyl groups with isocyanate to makepolyurethanes, and the blowing reaction of water with isocyanate torelease carbon dioxide for making foamed polyurethanes. It should benoted however that neither of the two groups of catalysts describedherein necessarily performs exclusively either gelling or blowingcatalysis functions. Rather, these labels indicate the primary functionof these catalyst components when used according to the invention.

As used herein, the term “polyurethane” is intended to mean polyurethaneand/or polyisocyanurate, as is understood in the art. Thus apolyurethane foam can be a polyurethane and/or polyisocyanurate foam.Typically, formation of the foam is aided by incorporation in thereaction mixture of a suitable blowing agent, as is known in the art.Typically a surfactant, such as a silicone surfactant, is also includedto help regulate foam formation, as is also known in the art.

Polyisocyanate

Polyurethane products made in accordance with the invention may beprepared using any suitable organic polyisocyanates well known in theart for making polyurethane foam including, for example, hexamethylenediisocyanates, isophorone diisocyanates, phenylene diisocyanates,toluene diisocyanates (TDI) and 4,4′-diphenylmethane diisocyanates(MDI). Especially suitable are mixtures of diisocyanates knowncommercially as “crude MDI”, marketed as PAPI by Dow Chemical, whichcontain about 60% of 4,4′-diphenylmethane diisocyanates along with otherisomeric and analogous higher polyisocyanates. Other suitableisocyanates are the 2,4- and 2,6-TDI's individually or together as theircommercially available mixtures. Also suitable are “prepolymers” ofthese polyisocyanates comprising a partially pre-reacted mixture of apolyisocyanate and a polyether or polyester polyol. Typically, the abovepolyisocyanates are used in an amount relative to the polyol toestablish an isocyanate index in the range of 80 to 400.

Polyol

Suitable polyols for making polyurethane foams in conjunction with thecatalyst compositions of the invention are those typically used in theart, including for example polyalkylene ether and polyester polyols.Polyalkylene ether polyols include poly(ethylene oxide) andpoly(propylene oxide) polymers and copolymers with terminal hydroxylgroups derived from polyhydric compounds, for example diols and/ortriols. Such diols and triols include, as non-limiting examples,ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol,1,6-hexanediol, neopentyl glycol, diethylene glycol, dipropylene glycol,pentaerythritol, glycerol, diglycerol, trimethylol propane, sugars suchas sucrose, and other low molecular weight polyols. Also useful areamine polyether polyols which can be prepared by reacting an amine, suchas ethylenediamine, diethylenetriamine, tolylenediamine,diphenylmethanediamine, triethanolamine or the like, with ethylene oxideor propylene oxide.

In the practice of this invention, a single high molecular weightpolyether polyol such as described above may be used. Also, mixtures ofsuch high molecular weight polyether polyols, for example mixtures ofdifferent multifunctional materials and/or of compounds having differentmolecular weights or different chemical compositions, may be used.Useful polyester polyols include those produced by reacting adicarboxylic acid with an excess of a diol, for example, adipic acid orphthalic acid anhydride with ethylene glycol or butanediol, or reactinga lactone such as caprolactone with an excess of a diol such aspropylene glycol.

In addition to the polyester and polyether polyols noted above, thepolyol component of the polyurethane formulation frequently comprises apolymer polyol. Such polymer polyols my be used in polyurethane foams toincrease the foam's resistance to deformation, i.e. to increase theload-bearing properties of the foam. One type of polymer polyol,referred to in the art as a graft polyol, consists of a triol in whichvinyl monomers are graft copolymerized. Styrene and acrylonitrile arethe usual monomers of choice. A second type, a polyurea modified polyol,is a polyol containing a polyurea dispersion formed by the reaction of adiamine and TDI. The TDI is typically used in excess, and therefore someof the TDI may react with both the polyol and polyurea. The second typeof polymer polyol may for example be a material called a PIPA polyol,which is formed by the in-situ polymerization of TDI and alkanolamine inthe polyol. Depending on the load-bearing requirements and otherparameters, polymer polyols may comprise 20-80% of the polyol portion ofthe polyurethane formulation. If polymer polyols constitute a part ofthe overall polyol charge, their weight is included in the total polyolweight for purposes of calculating the relative amounts of otheringredients according to the pphp (parts per hundred parts polyol)convention.

Blowing Agent

Blowing agents used according to the invention for making polyurethanefoams are any commonly used blowing agents known in the art. Theseinclude, as nonlimiting examples, HCFC (hydrochlorofluorocarbon)compounds, HFC (hydrofluorocarbon) compounds, chlorofluorocarbons,pentanes, and mixtures of these. The formulations contain water,typically at between 0.1 and 7 pphp (parts per hundred parts of polyol),more typically between 2.5 and 4.5 pphp, to produce CO₂ to help create afoam.

Catalyst Composition

Catalyst compositions according to the invention comprise mixturesof: 1) gelling catalysts selected from tertiary aminoalkyl substitutedprimary or secondary amines, and 2) blowing catalysts selected frombis(aminoalkyl) ethers comprising alkanol moieties, primary aminemoieties, or ureido moieties derived from such primary amine moieties.It is important that a combination of gelling and blowing catalystaccording to the invention be used, rather than either one alone or incombination with a catalyst not of this invention, in order to obtainthe low odor and low volatiles emission provided by the invention.Detailed descriptions of the gelling and blowing catalysts follow.

Gelling Catalysts

Gelling catalysts suitable for use according to the invention arerepresented by the general formula:

in which:

A represents CH or N,

R¹ represents hydrogen or the group

n represents an integer between 1 and 3, inclusive,

R² and R³ each represent hydrogen or a C1-C6 alkyl group, and

R⁶ represents H or 3-aminopropyl, provided that:

when A is N, R⁴ and R⁵ each represents a C1-C6 alkyl group or togetherrepresent a C2-C5 alkylene group which may contain a ring amine moiety—NR—, where R is hydrogen, a C1-C4 alkyl group, or the group

and

when A is CH, R⁴ and R⁵ together represent a C2-C5 alkylene groupcontaining a ring amine moiety —NR—, where R is a C1-C4 alkyl group orthe group

In one embodiment of the invention, R⁴ and R⁵ are each a methyl group, Ais nitrogen, and R² and R³ are each hydrogen. In another embodiment ofthe invention, A is CH, n is an integer between 1 and 3, inclusive, andR⁴ and R⁵ together constitute —CH₂CH₂N(CH₃)CH₂—.

Illustrative examples of tertiary aminoalkyl substituted primary orsecondary amines suitable for use according to the invention include3-dimethylaminopropylamine, N,N,N″,N″-tetramethyldipropylenetriamine,and N,N-bis(3-dimethylaminopropyl)-1,3-propanediamine. Reference to thepreparation of these compounds can be found in GB 1,338,275 and U.S.Pat. No. 4,248,930.

Blowing Catalysts

Blowing catalysts suitable for use according to the invention arebis(aminoalkyl) ethers comprising alkanol moieties, primary aminemoieties, or ureido moieties derived from such primary amine moieties,as represented by the general formula:

wherein:

R⁷, R⁸, and R⁹ each independently represents a C1-C4 alkyl group;

R¹⁰ represents H, a C1-C4 alkyl group, a C6-C20 aryl group, or a C6-C20aralkyl group;

m, p, and q each independently represents an integer between 1 and 4,inclusive; and Z represents —OH, —NH₂, —NH—CO—NH₂, or

In one embodiment of the invention, the blowing catalyst according tothe above structure is such that R⁷, R⁸, and R⁹ are each a methyl group,m and p are each equal to 2, and q is either 2 or 3.

In other embodiments, the blowing catalyst may comprise one or more ofN,N,N′-trimethyl-N′-2-hydroxyethylbis(aminoethyl) ether,N,N,N′-trimethyl-N′-3-aminopropylbis(aminoethyl) ether, andN,N,N′-trimethyl-N′-3-ureidopropylbis(aminoethyl) ether. Reference tothe preparation of these compounds can be found in U.S. Pat. Nos.4,433,170; 6,051,527; and 5,824,711; respectively.

In one embodiment of the invention, some or all of either the gelling orthe blowing catalyst, or both, may be in the form of a correspondingcarboxylic acid salt. It should be noted that the catalyst as added to apolyurethane formulation may contain the carboxylic acid alreadypresent, or the acid may be added with one or more of the otheringredients in the formulation, thereby forming the salt in situ. Byproviding the catalyst composition in the form of such a salt, a delayedonset of catalyst activity may be achieved. This may be beneficial insome applications, for example where a delay in viscosity increase isdesired in order to facilitate mold filling.

Many carboxylic acids are suitable for preparing salts of the gellingand/or blowing catalyst components according to the invention.Nonlimiting examples include formic acid, acetic acid, propionic acid,2-ethylhexanoic acid, aryloxy-substituted carboxylic acids such asphenoxyacetic acid and (dichlorophenoxy)acetic acid, and halogenatedacids such as 2-chloropropionic acid and a ring-halogenated aromaticcarboxylic acids such as chlorobenzoic acid. Further nonlimitingexamples of suitable acids include hydroxy acids such as gluconic acid,hydroxyacetic acid, tartaric acid, and citric acid. It will beunderstood by those of ordinary skill in the art that certain acids incombination with certain gelling/blowing catalyst combinations, andunder certain overall compositions of the polyurethane formulation, maydetract from the low-emission performance of the catalyst compositionsof the present invention. It will further be understood that thedetermination of acceptable combinations of acids with catalysts for agiven application may therefore require some amount of routineexperimentation, such as is within the ability of the skilled artisan,with such combinations still falling within the scope of the invention.

A catalytically effective amount of the catalyst composition comprisingthe gelling and blowing catalysts is used in the polyurethaneformulation. More specifically, suitable amounts of the catalystcomposition may range from about 0.01 to 10 parts by wt per 100 partspolyol (pphp) in the polyurethane formulation, preferably 0.05 to 4pphp. Suitable weight ratios of gelling catalyst to blowing catalyst inthe catalyst composition depend inter alia upon the particularingredients in the formulation, but are typically at least 2:1,preferably at least 4:1, and at most 10:1, preferably at most 6:1. ForTDI-based polyurethane formulations, a ratio of 2:1 to 4:1 is typical,while for MDI-based formulations a ratio from 3:1 to 10:1 is typical.

Variations in these ratios may be made according to the particularchoice of other ingredients (polyols, polyisocyanates, etc.) in thepolyurethane formulation, as commonly practiced in the art. Catalystcompositions according to the invention may also comprise other tertiaryamines, organotin or carboxylate urethane catalysts, such as are wellknown in the urethane art.

Other Ingredients

Other typical ingredients that may optionally be used in polyurethanefoam formulations made with the catalyst compositions of the inventioninclude flame retardants, chain extenders such as ethylene glycol andbutanediol; crosslinkers such as diethanolamine, diisopropanolamine,triethanolamine and tripropanolamine; and cell stabilizers such assilicones.

Preparation of polyurethane foams according to the invention can becarried out by conventional means for making polyurethane foam, usingthe catalyst compositions of this invention in place of previously usedcatalyst systems.

A typical polyurethane flexible foam formulation containing a catalystcomposition comprising a gelling catalyst and a blowing catalystaccording to the invention comprises the following components in partsby weight (pbw): Flexible Foam Formulation pbw Polyol  20-100 PolymerPolyol 80-0  Silicone Surfactant   1-2.5 Blowing agent   2-4.5Crosslinker 0.5-2   Catalyst Composition* 0.1-4   Polyisocyanate NCOIndex = 70-115*5:1 weight ratio of gelling catalyst to blowing catalyst

As used in herein, the term “NCO Index” means isocyanate index, as thatterm is commonly used in the polyurethane art. Use of this term in atable of formulations indicates that the appropriate amount ofpolyisocyanate should be used in order to achieve a formulation havingthe indicated NCO index.

EXAMPLES

The gelling and blowing catalysts used in the examples are abbreviatedas shown in the following table. Catalyst Structure BN,N-bis(3-dimethylaminopropyl)-N-isopropanolamine CN,N,N″,N″-tetramethyldipropylenetriamine EN,N,N′-trimethyl-N′-2-hydroxyethylbis(aminoethyl) ether FN,N-bis(3-dimethylaminopropyl)-1,3-propanediamine

Polyurethane foams were prepared using a variety of catalystcompositions, including some according to the invention and someaccording to standard industry practice. Thermal desorption of volatilematerials was performed on the foams, according to dynamic headspacetesting method VDA 278.

VDA 278 is a standard polyurethane foam emission testing method used inthe automotive industry to evaluate emissions from polyurethane foamunder realistic conditions. In a dynamic headspace experiment, gasextraction is carried out continuously. By continuously removing the gasphase, volatile analytes are unable to re-establish equilibrium andultimately all of the volatiles are removed from the sample, allowing amore accurate quantitative assessment.

The test method consists of two consecutive steps. In the first step,gaseous emissions, i.e. emissions that contribute to contamination ofthe interior air of cars, are measured at 90° C. for 0.5 h (VOC). Thefoam sample is placed in a thermo desorption tube. While beingcontinuously flushed with an inert gas, this tube is conditioned for 0.5h at 90° C. Volatiles emitting from the foam are trapped at −150° C. ina cryogenic trap. The trap is then heated to 280° C., transferring thevolatiles to a gas chromatograph (GC) column, where they are separated.

In the second step, condensable emissions, i.e. emissions thatcontribute to fogging in cars, are measured (FOG). This analysis isperformed on the sample after it has been submitted to the VOC test. Thesample is conditioned at 120° C. for 60 minutes, volatiles are againtrapped at −150° C., and the cryogenic trap is heated to transfer thevolatiles to the GC column, where they are separated. After separationof the VOC- and FOG- emissions by GC, the emitted components arechemically identified by automated searching of a mass spectrumdatabase.

Example 1

Evaluation of MDI Foam Thermal Desorption Testing According to VDA 278Method

Three machine mixed MDI pad foams (approximately 45 Kg/m³ density) wereprepared according to the formulation in Table 1, each of the threeincluding blowing catalyst E and one of gelling catalysts B, C, and F.Combinations 2 and 3 comprising gelling catalysts C and F, respectively,are according to the invention, while combination 1 comprising gellingcatalyst B is not. TABLE 1 MDI-formulation 1 2 3 Polyether polyol (OHNo. = 28) 100 100 100 Water 3.5 3.5 3.5 Diethanolamine (crosslinker) 0.50.5 0.5 DABCO DC 2525 Silicone Surfactant 1.0 1.0 1.0 Catalyst B 0.8Catalyst C 0.9 Catalyst F 0.6 Catalyst E 0.2 0.2 0.2 Cell opener* 1.51.5 1.5 MDI (32.5%) 59.0** 59.0** 59.0***Voranol CP 1421 polyether polyol, available from The Dow ChemicalCompany of Midland, MI**Amount calculated to provide an NCO Index of 95.

DABCO® DC 2525 silicone surfactant is available from Air Products andChemicals, Inc. of Allentown, Pa.

The formulations of Table 1 represent an standard industrial MDI-seatingformulations, except that formulations 2 and 3 use catalyst compositionsaccording to the invention, as noted above. Foam was made with differentcatalyst packages. Use levels were matched to get equivalent foamreactivity profiles. Gelling catalysts B, C, and F were blended withblowing catalyst N,N,N′-trimethyl-N′-2-hydroxyethylbis(aminoethyl) ether(catalyst E) to control foam density.

Table 2 shows the results when pad foams made according to theformulations of Table 1 were evaluated according to the VOC portion ofthe VDA 278 method. TABLE 2 Formulation 1 2 3 Volatile MaterialPolypropylene glycol 137 ppm 116 ppm 10 ppm oligomers Siloxanes  20 ppm 21 ppm  2 ppm Others  14 ppm  10 ppm  41 ppm Decomposition — — —products from catalysts TOTAL 171 ppm 147 ppm 53 ppm

The results show that at 90° C./0.5 h, lower emissions were observed forformulations 2 and 3 according to the invention than for formulation 1,in which the catalyst combination (gelling catalyst B plus blowingcatalyst E) is not according to the invention. The results shown inTable 2 point up the fact that, as noted above, both the gelling andblowing catalyst must be defined as set forth above. In formulation 1,blowing catalyst E is according to the invention, but gelling catalyst Bis not, and therefore the catalyst composition of B plus E is notaccording to the invention.

Table 3 shows the results of pad foams evaluated according to the FOGportion of the VDA 278 method. TABLE 3 Formulation 1 2 3 VolatileMaterials Polypropylene glycol 164 ppm 216 ppm  24 ppm oligomersSiloxanes —  22 ppm — Decomposition 190 ppm — — products from catalystsOthers 123 ppm  71 ppm 113 ppm TOTAL 477 ppm 309 ppm 137 ppm

The results shown in Table 3 reveal significantly higher FOG values forformulation 1 comprising catalyst compositions not according to theinvention, than for formulations 2 and 3 comprising catalystcompositions according to the invention.

CONCLUSION

The results detailed above indicate that, under foam thermal desorptiontesting conditions, foam made with gelling catalyst B (not of thisinvention) in combination with blowing catalyst E (formulation 1)evolved significantly more volatile species than the combinations,according to the invention, of gelling catalyst C or F with blowingcatalyst E (formulations 2 and 3). In the particular case of formulation1, it is seen that catalyst decomposition products contributed heavilyto emissions during VDA 278 testing. The results shown in Example 1demonstrate that combinations of gelling catalysts and blowing catalystsaccording to the invention provide polyurethane foams having low levelsof volatile emissions.

Although the invention is illustrated and described herein withreference to specific embodiments, the invention is not intended to belimited to the details shown. Rather, it is intended that the scope ofthe claims that follow includes various modifications that may be madein the details while nevertheless achieving the effects of thisinvention.

1. A catalyst composition comprising: 1) a gelling catalyst representedby the general formula:

in which: A represents CH or N, R¹ represents hydrogen or the group

n represents an integer between 1 and 3, inclusive, R² and R³ eachrepresent hydrogen or a C1-C6 alkyl group, and R⁶ represents H or3-aminopropyl, provided that: when A is N, R⁴ and R⁵ each represents aC1-C6 alkyl group or together represent a C2-C5 alkylene group which maycontain a ring amine moiety —NR—, where R is hydrogen, a C1-C4 alkylgroup, or the group

when A is CH, R⁴ and R⁵ together represent a C2-C5 alkylene groupcontaining a ring amine moiety —NR—, where R is a C1-C4 alkyl group orthe group

and 2) a blowing catalyst according to the general formula:

wherein: R⁷, R⁸, and R⁹ each independently represents a C1-C4 alkylgroup; R¹⁰ represents H, a C1-C4 alkyl group, a C6-C20 aryl group, or aC6-C20 aralkyl group; m, p, and q each independently represents aninteger between 1 and 4, inclusive; and Z represents —OH, —NH₂,—NH—CO—NH₂, or


2. The catalyst composition of claim 1, wherein R⁴ and R⁵ are each amethyl group, A is nitrogen, and R² and R³ are each hydrogen.
 3. Thecatalyst composition of claim 1, wherein R⁷, R⁸, and R⁹ are each amethyl group, m and p are each equal to 2, and q is either 2 or
 3. 4.The catalyst composition of claim 1, wherein A is CH, n is an integerbetween 1 and 3, inclusive, and R⁴ and R⁵ together constitute—CH₂CH₂N(CH₃)CH₂—.
 5. The catalyst composition of claim 1, wherein thegelling catalyst comprises N, N, N″, N″-tetramethyldipropylenetriamine.6. The catalyst composition of claim 1, wherein the gelling catalystcomprises 3-dimethylaminopropylamine.
 7. The catalyst composition ofclaim 1, wherein the gelling catalyst comprises N,N-bis(3-dimethylaminopropyl)-1,3-propanediamine.
 8. The catalystcomposition of claim 1, wherein the blowing catalyst comprisesN,N,N′-trimethyl-N′-2-hydroxyethylbis(aminoethyl) ether.
 9. The catalystcomposition of claim 8, wherein the gelling catalyst comprisesN,N,N″,N″-tetramethyldipropylenetriamine.
 10. The catalyst compositionof claim 8, wherein the gelling catalyst comprises3-dimethylaminopropylamine.
 11. The catalyst composition of claim 8,wherein the gelling catalyst comprisesN,N-bis(3-dimethylaminopropyl)-1,3-propanediamine.
 12. The catalystcomposition of claim 1, wherein the blowing catalyst comprisesN,N,N′-trimethyl-N′-3-aminopropylbis(aminoethyl) ether.
 13. The catalystcomposition of claim 1, wherein the blowing catalyst comprisesN,N,N′-trimethyl-N′-3-ureidopropylbis(aminoethyl) ether.
 14. Thecatalyst composition of claim 1, further comprising a carboxylic acidthat forms a salt with one or both of the gelling catalyst and theblowing catalyst.